The present invention relates to a brake fluid reservoir warning arrangement which responds when the fluid level drops below a predetermined minimum, comprising two contact pins and a contact disc arranged at a float to electrically connect the contact pins when the fluid level is low, and with a checking arrangement to check the reservoir warning arrangement.
Such brake fluid reservoirs with a warning arrangement and a checking arrangement to check the warning arrangement are known. German Patent DE-OS No. 2,345,870, for instance, shows a brake fluid reservoir of the type referred to. The warning arrangement is disposed in a domal member which is integrally formed with the upper part of the brake fluid reservoir. The rod of the float extends from below into the domal member and carries close to the upper end an annular contact plate. Two contact pins extend into the domal member laterally so that their contact rivets are underneath the contact disc which establishes a connection between the two contact pins when the fluid level is at its predetermined minimum. At its upper end the domal member possesses a kind of thimble made from compressible plastics.
Extending into the thimble is the upper end of the float rod. To check the function of the warning arrangement, the thimble-shaped member is compressed which displaces the float rod downwards. The contact disc connects the two contact pins, and the warning arrangement indicating that the brake fluid level is too low and must go on. If this is not the case, the indicator circuit is defective.
In these known warning arrangements, a compromise must be arrived at when dimensioning the thimble shaped parts because these parts must be so rigid that they are able to withstand the pressure occurring when the brake system is filled with brake fluid and at the same time they must remain elastic enough to be pressed down without major effort for a check of the reservoir warning arrangement. These are partly contradictory requirements.